Ultrasound effect on molecular weight reduction of amylopectin

Abstract

Amylopectin is a major polymer found in native starch granules and presents wide applicability as a biomaterial because of its low cost and biocompatibility. However, in many cases, the use of polysaccharides with low molecular weight is needed, mainly due to the possibility to produce functionalized nanomaterials, as well as to increase their diffusion quality. An effective technique for reducing the molecular weight of polysaccharides without chemical structure alteration is the ultrasound technique. In this paper, amylopectin solubilized in DMSO 90% (v/v) was submitted to ultrasound treatment under various conditions. For the evaluation before and after ultrasound treatment, laser light scattering (LLS) techniques, and viscosity measurements accompanied by pH, conductivity and temperature observations were carried out. As a result of the ultrasound treatment a decrease in the size of the polymer chains and solution viscosity were observed in all the conditions analyzed, demonstrating a low-cost method for reducing the molecular weight of amylopectin.

Chemical modification of cashew gum with acrylamide using an ultrasound‐assisted method

“…The value of the apparent R h was determined by DLS at a 90° angle through the Stokes–Einstein equation [Eq. ], where is the Boltzmann constant (1.38 × 10 −23 J K −1 ), is the temperature system, is the solvent viscosity, and is the diffusion coefficient, calculated by the equipment itself …”

Study of complexes formation between transition metal ions and amylopectin in DMSO/H2O solution

“…Amylopectin was extracted and purified from regular cassava starch as reported previously . Briefly, regular cassava starch (4.0 g/L) was dissolved in 90% DMSO and 10% distilled water.…”

“…It is known that starch‐water solutions are unstable due to gelatinization and retrogradation phenomena, on the other hand, starch solutions in a mixed solvent system are relatively stable . The use of mixed solvents such as DMSO/H 2 O facilitate the solubility of starch and its polymers at room temperature , and the solution viscosity is not changed as there is no gelatinization. Thus, the polymer‐solvent interaction with other species with electronic availability is promoted .…”

“…As cited before, some studies concerning the coordination of starch and its polymers with various metals ions can be found in the literature . However, the formation of metal complexes with amylopectin nanoparticles (R h = 105 nm ) in organic solvent is not found in the literature. Amylopectin nanoparticles would facilitate complexation due to increased surface area and mobility of the nanoparticle polymer chains, and the DMSO would extend the applicability of these new complexes due to its compatibility with organic compounds.…”

Effect of vibration duration of high ultrasound applied to bio-composite while gelatinized on its properties

“…The ultrasound can affect starch dispersions and damage the starch granules [8]. High power of ultrasonic is able to reduce the molecular weight of amylose and amylopectin due to breakage of C-C bonds, which leads to a decrease in viscosity [9,10,7]. Furthermore, swollen starch granules and aggregates can be solubilized, including ''ghost" granules which remain even after the full gelatinization of starch dispersion [6].…”